Ask HN: Can cycling be less CO2 efficient than driving an EV?

The TL;DR of my computation, which is extremely likely to be completely wrong is that in some cases you might be better driving an EV than a riding a bicycle in terms of CO2 emissions during usage, and that even taking manufacturing into account, EVs might still be not that much higher than the emissions of a bicycle.

The reason why I'm posting this here is that I'd like feedback on it.

The gist of it is that EVs being highly efficient, the source of food of the biker can actually make them less efficient than a car in terms of CO2 emissions during usage.

I can post sources for the numbers I describe, but I'm mostly interested in methodological flaws, still, don't hesitate to ask for them if necessary.

Here goes the computation:

Let's start by considering the CO2 emissions required to produce the food that fuels a human when they pedal a bicycle. Suppose the production of this food generates 0.000363 g of CO2 per joule of energy. Knowing that it takes about 110 joules to travel a meter by bicycle, we can deduce that the production of food to support cycling generates about 0.040 g of CO2 per meter traveled (110 joules * 0.000363 g/joule).

Now, let's compare this to a Tesla Model 3. This electric car requires about 0.15 Wh of energy to travel one meter, or 0.00015 kWh. In France, the production of 1 kWh of electricity emits about 100 g of CO2. Therefore, the Tesla Model 3 emits about 0.015 g of CO2 for each meter traveled (0.00015 kWh/meter * 100 g/kWh).

In this case, based solely on the usage of the vehicle or the bicycle and not their manufacture, the Tesla Model 3 is approximately 2.67 times less CO2 emitting than cycling (0.040 g/meter divided by 0.015 g/meter).

However, these figures do not take into account the CO2 emissions generated during the production of the vehicle or bicycle. If we refer to Tesla's 2020 impact report, we learn that when accounting for both the manufacture of the vehicle and its usage, and assuming the vehicle is powered by solar energy, emissions amount to about 0.062g of CO2 per meter traveled.

As for the bicycle, it is estimated that the production of a bicycle generates about 0.005g of CO2 per meter traveled. Adding this to the emissions of 0.040g per meter traveled generated by the production of food for the cyclist, we get a total of about 0.045g of CO2 per meter traveled.

Taking into account manufacturing and usage, the Tesla Model 3 therefore emits approximately 37% more CO2 per meter traveled than cycling (0.062 g/meter versus 0.045 g/meter). However, this comparison holds for single use. If the car is shared among multiple passengers, its carbon footprint per passenger and per meter could be substantially reduced, making the Tesla Model 3 potentially more eco-friendly than cycling depending on the number of passengers.

WDYT ?